If an article is set to featured, I need to show this first in all order scenarios. I know I can use array_multisort to sort using featured and price but the following is showing the featured first, but not then putting them into the price sort order.

I think you want $sort['region'] for the none condition. You might consider this slight change: <option value="regionasc">Select a Sort option</option> for consistency. Might you (in the future) consider a separate checkbox that offers "Featured First" separate from the select field? or are you happy to leave as is?
– mickmackusaSep 25 '18 at 23:09

I'm not a big fan of switch-case blocks, but because every condition is comparing $sortopt, it is a perfect candidate for single comparison handling.
– mickmackusaSep 25 '18 at 23:16